Deep level mining is widely practised throughout South Africa, particularly in the gold sector, where the extraordinary depths of vertical hoisting present an array of challenges. The accurate and secure positioning of a conveyance next to a station has been and continues to be one of the unresolved challenges that have led to many serious injuries and equipment damage. The literature study presented in this dissertation highlights some of the complexities associated with properly docking a conveyance and investigates some current, proposed and similar systems to address the issue. From the study it was found that no satisfactory device existed prompting a systematic design of a conveyance arresting device capable of securing a conveyance in a vertical shaft at any level. Proper definition of the system requirements was obtained and summarised into 16 groups. The system requirements play an important role in the design process by setting the direction but also featuring in concept screening and evaluation. In order to generate concepts a variety of creativity inspiring techniques were employed facilitating a systematic search for a solution. Application of the techniques, Brainstorming, Synectics, TRIZ, 2500 Engineering Principles, Sourcebooks and a Morphological chart resulted in the synthesis of 9 concepts. Screening and evaluation was performed on these concepts and the most suitable concept identified. The proposed concept is a simple system where two sets of beams are extended into the shaft in order to have the conveyance settle onto the supporting shaft steelwork. Once the conveyance came to a rest on the steelwork a second set of beams are extended beneath the steelwork to positively lock the conveyance in position. This required the geometric design of the system to ensure adequate strength to satisfy a factor of safety of ten. Design decisions were made on the section properties of the clamp beam by comparing a solid section and a box section. A supporting frame is used to guide the beams, with consideration given to the most appropriate method of attaching this support frame to the conveyance. The first choice was to have the beams extend from the rear of the conveyance but due to the moments and forces involved the conveyance roof structure could not support this configuration. The support frame was instead affixed directly to the conveyance Transom. In order to support the findings of the conventional calculations performed on the system components the system was subjected to finite element analysis. The results obtained from the simulation corresponded well for the simple components and varied somewhat in the more complex shapes attributed to the assumptions made to ease the conventional calculations. Weight and reliability in a harsh shaft environment was identified as critical design parameters and motivated the use of exotic high strength materials. The high strength of the materials made is possible to design a system with practical dimensions of adequate strength supported by the conventional and modelled calculations. Even though high strength materials were used in the design the overall system weigh is dissatisfying. A potentially successful and practical device was designed but certain factors such as weight, cost, conveyance structure and infrastructure modifications threaten the implementation of the design. This dissertation sets a sound foundation for future development and the continued search for a practical simple solution to this age old challenge. / MIng (Mechanical Engineering), North-West University, Potchefstroom Campus, 2015

Deep level mining is widely practised throughout South Africa, particularly in the gold sector, where the extraordinary depths of vertical hoisting present an array of challenges. The accurate and secure positioning of a conveyance next to a station has been and continues to be one of the unresolved challenges that have led to many serious injuries and equipment damage. The literature study presented in this dissertation highlights some of the complexities associated with properly docking a conveyance and investigates some current, proposed and similar systems to address the issue. From the study it was found that no satisfactory device existed prompting a systematic design of a conveyance arresting device capable of securing a conveyance in a vertical shaft at any level. Proper definition of the system requirements was obtained and summarised into 16 groups. The system requirements play an important role in the design process by setting the direction but also featuring in concept screening and evaluation. In order to generate concepts a variety of creativity inspiring techniques were employed facilitating a systematic search for a solution. Application of the techniques, Brainstorming, Synectics, TRIZ, 2500 Engineering Principles, Sourcebooks and a Morphological chart resulted in the synthesis of 9 concepts. Screening and evaluation was performed on these concepts and the most suitable concept identified. The proposed concept is a simple system where two sets of beams are extended into the shaft in order to have the conveyance settle onto the supporting shaft steelwork. Once the conveyance came to a rest on the steelwork a second set of beams are extended beneath the steelwork to positively lock the conveyance in position. This required the geometric design of the system to ensure adequate strength to satisfy a factor of safety of ten. Design decisions were made on the section properties of the clamp beam by comparing a solid section and a box section. A supporting frame is used to guide the beams, with consideration given to the most appropriate method of attaching this support frame to the conveyance. The first choice was to have the beams extend from the rear of the conveyance but due to the moments and forces involved the conveyance roof structure could not support this configuration. The support frame was instead affixed directly to the conveyance Transom. In order to support the findings of the conventional calculations performed on the system components the system was subjected to finite element analysis. The results obtained from the simulation corresponded well for the simple components and varied somewhat in the more complex shapes attributed to the assumptions made to ease the conventional calculations. Weight and reliability in a harsh shaft environment was identified as critical design parameters and motivated the use of exotic high strength materials. The high strength of the materials made is possible to design a system with practical dimensions of adequate strength supported by the conventional and modelled calculations. Even though high strength materials were used in the design the overall system weigh is dissatisfying. A potentially successful and practical device was designed but certain factors such as weight, cost, conveyance structure and infrastructure modifications threaten the implementation of the design. This dissertation sets a sound foundation for future development and the continued search for a practical simple solution to this age old challenge. / MIng (Mechanical Engineering), North-West University, Potchefstroom Campus, 2015

No description available.

Recently, laser light sources of different regimes have emerged as an essential tool in the biophotonics research area. Classic applications include, for example: manipulating single cells and their subcellular organelles, sorting cells in microfluidic channels and the cytoplasmic delivery of both genetic and non-genetic matter of varying sizes into mammalian cells. In this thesis several new findings specifically in the optical cell sorting as well as in the photo-transfection study fields are presented. In my optical cell sorting and guiding investigations, a new technique for enhancing the dielectric contrast of mammalian cells, which is a result of cells naturally engulfing polymer microspheres from their environment, is introduced. I explore how these intracellular dielectric tags influence the scattering and gradient forces upon these cells from an externally applied optical field. I show that intracellular polymer microspheres can serve as highly directional optical scatterers and that the scattering force can enable sorting through axial guiding onto laminin coated glass coverslips upon which the selected cells adhere. Following this, I report on transient photo-transfection of mammalian cells including neuroblastomas (rat/mouse and human), embryonic kidney, Chinese hamster ovary as well as pluripotent stem cells using a tightly focused titanium sapphire femtosecond pulsed laser beam spot. These investigations permitted advanced biological studies in femtosecond laser transfection: firstly, the influence of cell passage number on the transfection efficiency; secondly, the possibility to enhance the transfection efficiency via whole culture treatments of cells thereby, synchronizing them at the mitotic (M phase) as well as the synthesis phases (S phase) of the cell cycle; thirdly, this methodology can activate the up-regulation of the protective heat shock protein 70 (hsp70). Finally, I show that this novel technology can also be used to transfect mouse embryonic stem (mES) cell colonies and the ability of differentiating these cells into the extraembryonic endoderm.